var t:array[1..16, 1..16] of longint;
    a:array[1..100] of shortint;
    na,n,m:integer; smax:int64;

procedure init;
var i,j:integer; f:text;
begin
  assign(f, 'flip.in');
  reset(f);
  readln(f,n,m);
  na:=n + m;
  smax:=-1000000000;
  for i:=1 to n do
  for j:=1 to m do
  read(f, t[i,j]);
  close(f);
end;

procedure rez;
var f:text;
begin
  assign(f, 'flip.out');
  rewrite(f);
  write(f, smax);
  close(f);
end;


procedure calc;
var i,j:integer; s:int64;
begin
  s:=0;
  for i:=1 to n do
    for j:=1 to m do
      s:=s+t[i,j]*a[i]*a[n+j];
  if smax<s then smax:=s;
end;

procedure bin(p:integer);
begin
   if p>na then calc
   else begin
     a[p]:=-1; bin(p+1);
     a[p]:=1; bin(p+1);
   end;
end;

begin
  init;
  bin(1);
  rez;
end.